Hydraulic set liner hanger

ABSTRACT

A liner hanger employing a hydraulically actuated setting tool structure which is removable substantially entirely after setting of the hanger leaving a minimal amount of hanger structure in the well. A dog-type latch provides an improved releasable connection between the setting tool and the hanger and a reset spring is provided in the event of premature setting of the hanger to enable release of the hanger for movement to the desired location.

United States Patent Inventor Chudleigh B. Cochran Houston, Tex.

Appl. No. 21,122

Filed Mar. 19,1970

Patented Sept. 28, 1971 Assignee Brown Oil Tools, Inc.

Houston, Tex.

HYDRAULIC SET LINER HANGER 7 Claims, 11 Drawing Figs.

U.S. Cl 166/208, l66/I24, 166/212 Int. Cl E21b43/10, F2 1 b 33/T29 Fieldof Search 166/124,

[ 5 6] References Cited UNITED STATES PATENTS 2,442,529 6/1948 Clark166/124 3,253,655 5/1966 Brown 166/124 3,260,309 7/1966 Brown 166/1243,342,268 9/1967 Brown 166/124 Primary Examiner-James A. LeppinkAtt0rneyR. Werlin 5 ABSTRACT: A liner hanger employing a hydraulicallyactuated setting tool structure which is removable substantiallyentirely after setting of the hanger leaving a minimal amount of hangerstructure in the well. A dog-type latch provides an im- PATENTED strzsIan SHEU t 0F 4 wk: A TTORNEY HYDRAULIC SET LINER HANGER Liner hangersare employed to secure an inner pipe string or liner to an outer pipestring or casing in a well bore generally preparatory to cementing theliner in place in the well bore to seal off the surrounding earthformations.

Generally speaking, the liner hanger is secured to the upper end of theliner string and is run on a setting tool assembly which functions tosecure the liner to the surrounding casing and to aid in the subsequentcementing operation. In more conventional liner hangers, substantialportions of the setting assembly form integral parts of liner hanger andmust remain in the well, thereby substantially increasing the cost ofthe liner hanger to the well operator, as well as increasing thecomplexity of the operations involved in setting the hanger andconducting the subsequent cementing operations.

The present invention is directed to a greatly simplified liner hangerin which the setting tool is actuated by hydraulic pressure to anchorthe liner to the surrounding casing, and is retrievable substantially inits entirety when setting is completed leaving only minimal hangerstructure in the well.

In accordance with a preferred embodiment of this invention, the hangerbody employs a multicone and slip construction which greatly reduces theoverall length of the hangeritself. The setting tool includes a mandrelwhich carries a setting collar slidably mounted thereon and releasablyattached to the hanger setting sleeve by a positive dog-type latch whichassures against premature setting of the hanger during running. Thesetting collar embodies a cylinder communicating with the bore of themandrel for admitting pressure fluid to actuate the hanger. A floatingnut provides a releasable connection between the mandrel and the hangerwhich upon release, enables the setting tool to be withdrawn from thehanger. Spring means is provided in compression between the mandrel andthe setting collar which functions to permit release of the hanger inthe event the hanger is prematurely set during running to thereby allowthe running of the hanger to be resumed without requiring the hanger tobe withdrawn from the well for resetting.

Other and more specific objects and advantages of this invention willbecome more readily apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawings which illustrateone embodiment of the invention and a modification thereof.

IN THE DRAWING FIGS. 1A, 1B, and 1C, together, comprise a longitudinalquarter-sectional view of the liner hanger and setting tool assembly,together with some related parts employed in the liner cementingoperation, but which do not themselves form a part of this invention,the tool parts being shown in the running position;

FIG. 2 is a longitudinal quarter-sectional view corresponding to FIG. 1Ashowing the hanger set in the surrounding well casing;

FIG. 3 is a view similar to FIG. 2 showing the setting tool releasedfrom the hanger body;

FIG. 4 is a view similar to FIG. 3 showing the setting tool completelyreleased from the hanger preparatory to withdrawal of the setting toolfrom the well;

FIG. 5 is a view similar to FIG. 4 showing the hanger in place andcemented, the setting tool being completely removed;

FIG. 6 is a longitudinal quarter-sectional view of modified form of theliner hanger, the parts being shown in the runningin position;

FIG. 7 is a view generally similar to FIG. 6 showing the hanger in theset position with the setting tool in the same positions as seen in FIG.2; and

FIGS. 8 and 9 are cross-sectional views taken on lines 8-8 and 9--9respectively, of FIG. IA.

Referring to the drawing, more particularly to FIGS. 1A to IC, thehanger structure comprises the liner hanger, per se, designatedgenerally by the letter A, and the setting tool structure designatedgenerally by the letter B, which is secured to the hanger structure andby means of which the tool string is run inside a well casing C, towhich the hanger A is to be attached.

Liner hanger A comprises a tubular body 10, the lower end of which has athreaded socket 1] for connection of the hanger to tee upper end of apipe string L which constitutes the liner to be anchored to the casingC. The exterior of hanger body 10 is provided with a stepped surface,the portions of which define successive upwardly and outwardly taperingfrustoconical surfaces 12-12, there being at least two of these steps onthe exterior of the body 10 to form expander cones. Surrounding body 10is a tubular cage 14 having a plurality of openings or windows 15 inwhich are mounted pipe-gripping slips 16, having their inner surfacesstepped in a manner complementary to the stepped expander surfaces 12,the complementary surfaces on the interior of the slips being indicatedby the numerals l717. Slips 16 are provided with buttress teeth 18 ontheir outer surfaces for biting into the wall of casing C, when theslips are moved outwardly and upwardly relative to hanger body 10.Downward movement of the slips with cage 14 relative to body 10 willcause slips to retract out of gripping engagement with casing C. Cage 14is held in its slip-retracting down position relative to hanger body 10by means of shear pins 20 which secure the cage to body 10. The upperend of cage 14 is secured to extension sleeve 22 which is termed thesetting sleeve in this description.

Setting tool B comprises the tubular mandrel 24, the upper end of whichis externally threaded for connection by means of a coupling 25, to arunning pipe string P and the lower end of which is connected to a sealnipple 28 carrying downwardly opening cup seals 30 for sealing off theannular space between the seal nipple and the wall of liner L (FIG. 1B).Mandrel 24 includes a sub 32 threadedly received at its upper end in athreaded socket 33 forming a portion of the mandrel and at its lower endin a socket 34 carried by the upper end of the seal nipple, thus formingthe connection between the latter and the mandrel. The ends of sockets33 and 34 define spaced-apart external shoulders 35 and 36,respectively.

The exterior of sub 32 between shoulders 35 and 36 is provided with oneor more longitudinally extending radial splines 37 on which a floatingnut 38 is slidably mounted. The exterior of nut 38 carries a section ofleft-hand threads 39 adapted to mate with a complimentary section ofthreads 40 formed in the inner wall of hanger body 10. By means of theleft-hand thread arrangement, rotation of the mandrel in the right-handdirection will cause nut 38 to move upwardly on splines 37 relative tohanger body 10 to effect release of this connection between the mandreland the hanger body when the nut has cleared threads 40 (FIG. 3).Mounted about sub 32 between shoulder 35 and the upper end of splines 37is an antifriction bearing 41 which is supported between shoulder 35 anda bearing shoulder 42 formed by the upper end of hanger body 10. Thisbearing arrangement aids rotation of the mandrel relative to the linerhanger during operation of the tools.

A setting collar 44 is slidably mounted about the upper portion ofmandrel 24 and carries spaced-apart internal packings 45-45 slidablysealing with the exterior of the mandrel to define between them acylinder 46 which is in communication with the bore of the mandrel viaone or more ports 47 which extend through the wall of the mandrel.Setting collar 44 is biased downwardly relative to the mandrel by meansof a coil spring 48 disposed about the upper end portion of mandrel 24in compression between the upper end of collar 44 and coupling 25.

The lower end portion of collar 44 is enlarged in diameter and isconnected to a tubular cage 49 concentrically spaced from the exteriorof mandrel 24 and dimensioned to extend between the latter and the upperend of setting sleeve 22. Cage 49 is provided with a plurality ofangularly spaced radial windows 50 in which latching dogs 51 are mountedfor radial movement. Dogs 51 are dimensioned to a radial thicknesssomewhat greater than that of the wall of cage 49 so as to presentshoulders exteriorly or interiorly of cage 49 depending on the directionin which the dogs are moved in windows 50. A latching sleeve 52 ismounted in the bore of cage 49 and is provided near its lower end withan external recess 53 adapted to receive dogs 51 when moved upwardlyinside cage 49 into registration with the dogs. Latching sleeve 52 isinitially held in its upper position (FIG. 1A) by means of shear screws54 connecting the sleeve to the cage. In this position sleeve 52 forcesdogs 51 outwardly of the cage and the upper end of setting sleeve 22 isprovided with an internal annular recess 55 to receive the thusoutwardly projected dogs. In the position shown in FIG. 1A, the dogs 51provide a positive connection between the running collar and the settingsleeve with provides greater assurance against untimely release of thesetting tool from the liner hanger during running of the tools than isafforded by the more conventional shear pins commonly used for acorresponding purpose.

As the liner hanger is commonly employed in conjunction with tools forcementing the liner in the well bore after it is secured to the casing,FIG. 1B shows a conventional cementing plug 60 releasably secured to thelower end of sea] nipple 28, and FIG. 1C illustrates a conventionallanding collar 61 mounted in the bore of casing C and provided with acentral opening 62 adapted to be closed by means of a ball 63 (shown inbroken lines) which is pumped down through the running string forclosing off the casing bore to permit buildup of fluid pressure insidethe liner hanger setting tool for purposes of setting the hanger as wellas for other purposes in connection with the cementing operation.

It will be understood that seal nipple 28, cementing plug 60 and landingcollar 61, do not, per se, form parts of the liner hanger structure ofthis invention, except insofar as they illustrate one means by whichfluid pressure can be directed into cylinder 46 of the setting collar.Other means for this purpose will be readily evident to those skilled inthe art to which the present invention pertains.

In operation, the liner hanger A connected to the top of liner L andwith setting tool B connected thereto with the respective parts in thepositions shown in FIGS. 1A to 1C, will be run into casing C on pipestring P. In this stage of operation running collar 44 will be securedto setting sleeve 22 and mandrel 24 connected to hanger body by means offloating nut 38.

When the tools have reached the desired point inside casing C, ball 63will be dropped through the bore of pipe string P and pumped down withfluid, such as mud, to its seat on landing collar 61 closing port 62,sealing off the casing, and allowing fluid pressure to build up insidethe bore of mandrel 24. The pressure will be transmitted through ports47 into cylinder 46 and exert upward pressure on collar 44 and thencethrough setting sleeve 22 to slip cage 14 with sufficient force to breakshear screws (FIG. 2), moving the cage upward relative to body 10. Thisrelative upward movement of the cage will force slips 16 upwardly andoutwardly over expander surfaces 17-17 until teeth 18 are caused to bitestrongly into the wall of easing C, thereby setting the liner hanger andsecuring the liner to the casing. The upward movement of the settingcollar on mandrel 24 will strongly compress spring 48. If for any reasonthe slips on the liner hanger have set prematurely during the running ofthe tools, it is only necessary to pick up on the running string,whereupon the force of the compressed string 48 will act to push settingcollar 44, setting sleeve 22 and slip cage 14 downwardly relative to themandrel to thereby push slips 36 downwardly and inwardly to theirretracted positions, freeing the tools for further downward movement asmay be required. The continued engagement of dogs 51 in recess 55provides a positive connection between the running collar and the linerhanger which enables the necessary manipulation of the tools withassurance against premature release of the setting tool from the linerhanger.

When the hanger is firmly set, running string P will be rotated in theright-hand direction causing floating nut to move upwardly to theposition releasing it from its connection to hanger body 10 (FIG. 3),thereby freeing the setting tool and its appended cementing tools formanipulation as may be required in conducting the operations forcementing the liner in the well. These operations will generally requiresome relatively short longitudinal movements of the setting tool whilethe cement is being placed and excess cement circulated out of the well.

Thereafter, to effect removal of the setting tool and its appended sealnipple, the other cementing tools being left in the well, upward pullwill be applied through the running string to the mandrel to pull thelatter upwardly. Running collar 44 will remain stationary through itsconnection to setting sleeve 22 which will be anchored to the casingwall by slips 16. The resulting relative upward movement of mandrel 24will bring a shoulder 65 on the exterior of the mandrel into abuttingengagement with the lower end of latching sleeve 52 (FIG. 4) withsufficient force to break shear pins 54 and raise sleeve 52 upwardlysufficiently to place recess 53 in registration with dogs 51. This willfree the latter to retract from recess 55, thereby releasing collar 44from setting sleeve 22. The entire setting tool assembly may now bewithdrawn from the well leaving only the relatively short liner hangerin the well as best seen in FIG. 5, where it is shown cemented to thecasing.

By providing the stepped conical surfaces on the hanger body, theoverall length of the hanger will be substantially reduced as comparedwith more common designs and it will be evident that minimal hangerstructure will be left in the well while the entire setting tool will bewithdrawn and may be reused in its entirety with other hangers, therebygreatly reducing the cost to the user.

FIGS. 6 and 7 illustrate a modification of the liner hanger involvingessentially a modified design of the slip cage and slips. In all otherrespects the parts are identical with those in the principal embodimentand bear the same numbers.

In this modification the slip cage comprises a ring 114 to which slips116 are pendently connected by spring arms 115. The slips have steppedinternal surfaces 117 complementary to the stepped expander surfaces12-12. The lower ends of the slips have downwardly and inwardly taperingsurfaces 118 adapted to be received in a keeper collar 119 having atapered inner surface 120 matching the taper of slip surfaces 118.Keeper collar 119 serves to hold the slips inwardly against expandersurfaces 1212 during the longitudinal movements of the slip cage duringsetting and releasing movements of the slips and to prevent prematureengagement with the casing while the tools are being run into thecasing. The operations of the setting tool in setting the hanger and ineffecting release of the setting tool from the hanger are otherwiseidentical with the operations described above in connection with thefirstdescribed embodiment.

It will be apparent that numerous changes and modifications may be madein the details of the illustrative embodiments without departing fromthe disclosed invention.

What I claim and desire to secure by Letters Patent is:

1. A liner hanger, comprising,

a. a tubular body connectable to a liner;

b. upwardly and outwardly tapering expander surfaces on the body;

c. a cage member slidable longitudinally on the body;

d. pipe-gripping slips carried by the cage member cooperating with saidexpander surfaces for radial movement into and out of grippingengagement with a surrounding well pipe in response to longitudinalmovement of said cage member relative to said body;

. a tubular setting sleeve secured to the upper end of said cage member;

f. a setting tool including a tubular mandrel extending through thebores of said sleeve and of said body and connectable to an operatingpipe string;

g. cooperating means connecting said mandrel to said body and releasabletherefrom by right-hand rotation of the mandrel relative to the body;

h. a fluid pressure-actuated latching collar longitudinally slidable onthe mandrel;

i. releasable latch means initially securing said collar to said settingsleeve and releasable therefrom in response to relative longitudinalmovement of said mandrel;

j. means resiliently urging said collar downwardly on said mandrel; and

k. means in said mandrel for directing operating pressure fluid to saidcollar.

2. A liner hanger according to claim 1, wherein said expander surfacesare of stepped configuration; and wherein said slips have stepped innersurfaces of complementary configuration.

3. A liner hanger according to claim 1, wherein said cage membercomprises a ring to which said slips are pendently supported by flexiblearm means, and wherein a keeper collar is mounted on said body toslidably receive the free ends of said slips.

4. A liner hanger according to claim 1, wherein said cooperating meanscomprises:

a. a nut having external left-hand threads splined for longitudinalnonrotative movement on said mandrel; and

b. a section of complementary threads in the bore of said body.

5. A liner hanger according to claim 1 wherein said latching collarcarries longitudinally spaced seals defining a cylinder surrounding saidmandrel; and ports through the wall of said mandrel communicating withsaid cylinder.

6. A liner hanger according to claim 1, wherein said releasable latchmeans comprises:

a. a tubular cage secured to said collar and extending concentricallyinto the upper end of said setting sleeve;

b. latch dogs mounted in the wall of said cage for radial movement intoand out of latching engagement with said setting sleeve; and

c. a latching sleeve mounted in the bore of the cage releasably securedtherein to initially hold said dogs in said latching engagement andreleasable by said relative longitudinal movement of said mandrel.

7. A liner hanger, comprising:

a. a tubular body connectable to a liner;

b. upwardly and outwardly tapering expander surfaces on said body, eachof said expander surfaces having a stepped configuration comprising atleast two successive steps;

0. a cage member slidable longitudinally on the body;

d. pipe gripping slips carried by the cage member having stepped taperedinner surfaces complementary to and cooperating with said expandersurfaces for radial movement into and out of gripping engagement with asurrounding well pipe in response to longitudinal movement of said cagemember relative to said body; and

e. setting means cooperating with said cage member for effecting saidrelative longitudinal movement thereof; said setting means including:

i. a tubular mandrel extending through said body and connectables to anoperating pipe string,

ii. a setting collar slidably mounted on said mandrel; and

iii. latch means releasably connecting said collar to said cage member.

1. A liner hanger, comprising, a. a tubular body connectable to a liner;b. upwardly and outwardly tapering expander surfaces on the body; c. acage member slidable longitudinally on the body; d. pipe-gripping slipscarried by the cage member cooperating with said expander surfaces forradial movement into and out of gripping engagement with a surroundingwell pipe in response to longitudinal movement of said cage memberrelative to said body; e. a tubular setting sleeve secured to the upperend of said cage member; f. a setting tool including a tubular mandrelextending through the bores of said sleeve and of said body andconnectable to an operating pipe string; g. cooperating means connectingsaid mandrel to said body and releasable therefrom by right-handrotation of the mandrel relative to the body; h. a fluidpressure-actuated latching collar longitudinally slidable on themandrel; i. releasable latch means initially securing said collar tosaid setting sleeve and releasable therefrom in response to relativelongitudinal movement of said mandrel; j. means resiliently urging saidcollar downwardly on said mandrel; and k. means in said mandrel fordirecting operating pressure fluid to said collar.
 2. A liner hangeraccording to claim 1, wherein said expander surfaces are of steppedconfiguration; and wherein said slips have stepped inner surfaces ofcomplementary configuration.
 3. A liner hanger according to claim 1,wherein said cage member comprises a ring to which said slips arependently supported by flexible arm means, and wherein a keeper collaris mounted on said body to slidably receive the free ends of said slips.4. A liner hanger according to claim 1, wherein said cooperating meanscomprises: a. a nut having external left-hand threads splined forlongitudinal nonrotative movement on said mandrel; and b. a section ofcomplementary threads in the bore of said body.
 5. A liner hangeraccording to claim 1, wherein said latching collar carrieslongitudinally spaced seals defining a cylinder surrounding saidmandrel; and ports through the wall of said mandrel communicating withsaid cylinder.
 6. A liner hanger according to claim 1, wherein saidreleasable latch means comprises: a. a tubular cage secured to saidcollar and extending concentrically into the upper end of said settingsleeve; b. latch dogs mounted in the wall of said cage for radialmovement into and out of latching engagement with said setting sleeve;and c. a latching sleeve mounted in the bore of the cage releasablysecured therein to initially hold said dogs in said latching engagementand releasable by said relative longitudinal movement of said mandrel.7. A liner hanger, comprising: a. a tubular body connectable to a liner;b. upwardly and outwardly tapering expander surfaces on said body, eachof said expander surfaces having a stepped configuration comprising atleast two successive steps; c. a cage member slidable longitudinally onthe body; d. pipe gripping slips carried by the cage member havingstepped tapered inner surfaces complementary to and cooperating withsaid expander surfaces for radial movement into and out of grippingengagement with a surrounding well pipe in responsE to longitudinalmovement of said cage member relative to said body; and e. setting meanscooperating with said cage member for effecting said relativelongitudinal movement thereof; said setting means including: i. atubular mandrel extending through said body and connectable to anoperating pipe string; ii. a setting collar slidably mounted on saidmandrel; and iii. latch means releasably connecting said collar to saidcage member.